1. Field of the Invention
The present invention relates to a magneto-resistance effect element bar exposure method, a magneto-resistance effect element bar formation method, and a magneto-resistance effect element bar.
2. Related Background Art
The increased capacity and miniaturization of magnetic disk devices as well as the higher recording densities thereof have established a need for improvements in the performance of thin-film magnetic heads.
The creation of a thin-film magnetic head involves first cutting a magneto-resistance effect element bar that comprises several tens to several hundreds of magneto-resistance effect elements (referred to hereinafter as MR elements) which are lined up in a row in the longitudinal direction of the bar, from a substrate. The cut faces parallel to the longitudinal direction are then polished to obtain an MR element bar that comprises MR elements that possess the desired MR element height, that is, a length (‘MR height’ hereinafter) which extends from the polished face-side end of the MR element as far as the end on the opposite side, the MR elements being processed separately to form thin-film magnetic heads.
Although the MR elements in the MR element bar are ideally lined up at equal intervals on a straight line, the MR elements are, in actual fact, lined up in positions which are somewhat displaced from the positions originally intended. Further, although several tens to several hundreds of MR elements in this single MR element bar are then polished under conditions which are thought to be optimum, when the positions of each of the MR elements are widely different, much less discontinuous, the distribution of the desired MR height is then poor, and the distribution of the element resistance of the MR elements and the MR rate of change is poor. As a result, a variation in the thin-film magnetic head characteristics is produced and hence the yield is poor.